Question

20/21+(-5/9)-3/1+8/7

Answer 1

LCM is 63

= 60-35-63+72/63

= 34/63

hope it helps you

Answer 2

Answer:

20/21+(-5/9)-3/1+8/7

20/21-5/9-3/1+8/7

20/21+8/7-5/9-3/1

{(20+24)/21}-{(5+27)/9}

(44/21-32)/9

132-224/63

-92/63